Making Milk Into Plastic Uploaded by Jetman

April 13, 2022 Post a Comment

Summary

xxx-45 minutes

1 to 2 days

chemic reaction, plastic, polymers, monomers

Teisha Rowland, PhD, Science Buddies

Sandra Slutz, PhD, Science Buddies

Introduction

Have you lot e'er heard that plastic tin be made out of milk? If this sounds like something made-upward to you, you may exist surprised to acquire that from the early on 1900s until about 1945, milk was commonly used to make many dissimilar plastic ornaments, including buttons, decorative buckles, beads and other jewelry, fountain pens, the backings for hand-held mirrors, and fancy comb and brush sets. Milk plastic (usually called casein plastic) was even used to make jewelry for Queen Mary of England! In this activity you volition brand your own casein plastic out of hot milk and vinegar.

This activity is not recommended for use as a science fair projection. Good science fair projects have a stronger focus on controlling variables, taking accurate measurements, and analyzing data. To find a science fair project that is just right for you lot, browse our library of over 1,200 Scientific discipline Off-white Project Ideas or use the Topic Selection Wizard to get a personalized project recommendation.

Materials

Milk (1 cup)
White vinegar (4 teaspoons)
Measuring cup
Measuring spoons
Optional: Thermos
Mug or other heat-resistant loving cup big enough to hold at least ane cup of milk
Paper towels
Spoon
Optional: Cookie cutters, glitter, food coloring, markers
Stovetop oven and pan or microwave and microwaveable container

Instructions

Heat ane loving cup of milk in a pan or stovetop until the milk is steaming. Alternatively, yous can microwave the milk in a microwaveable container by warming it at l% ability for 5 minutes. It should exist about the same temperature as yous would want milk to be for making hot cocoa. Heat for more time if needed.
If you cannot practice the remainder of the activity right abroad, store the hot milk in a thermos until it is needed.
Add 4 teaspoons (tsp.) of white vinegar to a mug or other oestrus-resistant loving cup.

Add the 1 cup of hot milk to the mug. Y'all should meet the milk form white clumps (curds).

Why practise yous think the milk forms curds when it is added to the vinegar? What do you recollect they are made of?

Mix the mug slowly with a spoon for a few seconds.

What happens when the milk and vinegar are mixed together? Why practise you remember this is?

Stack four layers of paper towels on a hard surface that is safety to get damp.
Once the milk and vinegar mixture has cooled a flake, use a spoon to scoop out the curds. You lot can practise this by tilting the spoon confronting the inside of the mug to let excess liquid drain out while retaining the curds in the spoon. Collect as many curds as y'all tin can in this way and put them on top of the paper towel stack.
Fold the edges of the paper towel stack over the curds and press down on them to absorb backlog liquid from the curds. Use extra paper towels if needed to soak up the rest of the extra liquid.

Knead all of the curds together in a brawl of dough. This is the casein plastic.

How exercise the kneaded curds feel and look differently than the curds did originally?

If you want to make the casein plastic into something, you tin can colour, shape, or mold it at present (within an hr of making the plastic dough) and leave it to dry on newspaper towels for at least 48 hours. In one case it has dried, the casein plastic will be difficult. Tip: To shape the plastic, the dough must be kneaded well. Molds and cookie cutters work well, or, with more patience, the dough can be sculpted. Food coloring, glitter, or other decorative bits can exist added to the wet casein plastic dough, and dried casein plastic can be painted or colored with markers.

Cleanup

To avoid bottleneck the sink discard whatsoever unused curds in the trash— do non pour them downward the sink.

What Happened?

When you added the hot milk to the vinegar, small, white chunks should accept go visible in the mixture. This is because adding an acid, such every bit vinegar, to the milk changes the pH of the milk and makes the casein molecules unfold and reorganize into a long chain, curdling the milk. The white chunks are curds. Yous should accept been able to use a spoon to separate the curds from most of the liquid. Boosted drying of the curds with the newspaper towels should take made the curds set up to knead in to a ball and use as casein plastic, which can be molded and decorated.

Digging Deeper

Plastics are a grouping of materials that tin look or feel different, but can all be molded into many shapes. The similarities and differences between different plastic products come up down to the molecules they are made of. Plastics are all similar because they are all made upwardly of molecules that are repeated over and over once more in a chain, called a polymer. Polymers can exist chains of one type of molecule, or bondage of different types of molecules linked together in a regular blueprint. In a polymer, a single repeat of the pattern of molecules is chosen a monomer (even if the polymer is made upward of only 1 type of molecule).

Milk contains many molecules of a protein called casein. When milk is heated and combined with an acid, such every bit vinegar, the casein molecules unfold and reorganize into a long chain. Each casein molecule is a monomer and the chain of casein monomers is a polymer. The polymer can be scooped up and molded, which is why plastic made from milk is called casein plastic.

Ask an Skillful

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For Further Exploration

How does the amount of vinegar used affect the yield of casein plastic? To find out you tin echo this activity, but in addition to testing 4 tsp. of white vinegar with 1 cup of hot milk, try likewise testing 1 tsp, two tsp, or 8 tsp of white vinegar, each with 1 cup of hot milk. To collect more of the curds and go a better idea of the yield of the casein plastic, instead of scooping out the curds with a spoon, y'all tin can pour the vinegar and milk mixture through a piece of cotton cloth (such as an quondam T-shirt) secured with rubber bands on elevation of a cup.
In improver to vinegar, there are a lot of other acids that we encounter in the kitchen all the time, such as lemon juice, orange juice, soda pop, and tomato juice. Do some of these mutual acids work better than others to make casein plastic?
Y'all used hot milk in this activeness that was non a specific temperature, but using hotter or colder milk might affect the casein plastic reaction. Design an experiment to investigate this. How does the temperature of the milk affect how much casein plastic you can produce?

Project Ideas

Scientific discipline Fair Projection Thought

"Plastic made from milk" —that certainly sounds similar something fabricated-upward. If you agree, you may be surprised to learn that in the early 20th century, milk was used to make many different plastic ornaments —including jewelry for Queen Mary of England! In this chemistry science project, you can figure out the best recipe to make your own milk plastic (ordinarily chosen casein plastic) and use it to make beads, ornaments, or other items. Read more

Careers

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Chemical engineers solve the issues that affect our everyday lives by applying the principles of chemistry. If you lot enjoy working in a chemical science laboratory and are interested in developing useful products for people, and so a career as a chemical engineer might be in your hereafter. Read more

Career Profile

What makes it possible to create high-engineering objects like computers and sports gear? Information technology's the materials inside those products. Materials scientists and engineers develop materials, like metals, ceramics, polymers, and composites, that other engineers need for their designs. Materials scientists and engineers think atomically (meaning they sympathize things at the nanoscale level), but they design microscopically (at the level of a microscope), and their materials are used macroscopically… Read more

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Source: https://www.sciencebuddies.org/stem-activities/milk-into-plastic

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